Gnidia glauca flower extract mediated synthesis of gold nanoparticles and evaluation of its chemocatalytic potential

Synthesis of AuNPs using GGFE was monitored by UV-Vis spectroscopy and was found to be rapid that completed within 20？min. The concentration of chloroauric acid and temperature was optimized to be 0.7？mM and 50°C respectively. Bioreduced nanoparticles varied in morphology from nanotriangles to nanohexagons majority being spherical. AuNPs were characterized employing transmission electron microscopy, high resolution transmission electron microscopy. Confirmation of elemental gold was carried out by elemental mapping in scanning transmission electron microscopic mode, energy dispersive spectroscopy and X-ray diffraction studies. Spherical particles of size ~10？nm were found in majority. However, particles of larger dimensions were in range between 50-150？nm. The bioreduced AuNPs exhibited remarkable catalytic properties in a reduction reaction of 4-nitrophenol to 4-aminophenol by NaBH4 in aqueous phase.The elaborate experimental evidences support that GGFE can provide an environmentally benign rapid route for synthesis of AuNPs that can be applied for various purposes. Biogenic AuNPs synthesized using GGFE exhibited excellent chemocatalytic potential.